<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div#outer{
            width: 300px;
            height: 300px;
            border: 1px solid red;
        }
        div#center{
            width: 200px;
            height: 200px;
            border: 1px solid red;
        }
        div#inner{
            width: 100px;
            height: 100px;
            border: 1px solid red;
        }
    </style>
    <script src="./vue.js"></script>
    <script>
        window.onload=function(){
            new Vue({
                el:'#app',
                data:{},
                methods:{
                    handler(event){
                        alert(event.currentTarget.id)
                    },
                    submit(event){
                        // event.preventDefault();
                    },
                    keyup(){
                        alert();
                    }
                }
            })
        }
    </script>
</head>
<body>
    <div id="app">
        <input type="text" v-on:keyup.enter='keyup'>
        <hr>
        <form action="1.html" v-on:submit.prevent='submit'>
            <h1>签到</h1>
            <input type="number">
            <button type="submit">submit</button>
        </form>
        <hr>
        <div id="outer" v-on:click.capture.once='handler'>
            <div id="center" v-on:click.capture='handler'>
                <div id="inner" v-on:click.capture='handler'></div>
            </div>
        </div>
    </div>
</body>
</html>